After tirelessly lobbying Congress since late summer, the first responders who spent months working at Ground Zero following the terrorist attacks on Sept. 11, 2001, are set to finally receive lifetime medical care for the illnesses attributable to their time on "the pile."

The James Zadroga 9/11 Health and Compensation Reauthorization Act is included in the must-pass $1.1 trillion spending package — also referred to as the omnibus — making what is essentially a permanent extension to the health care program for first responders.

Congressional leaders and the White House reached an agreement on the package late Tuesday, House Speaker Paul Ryan, R-Wi., told GOP lawmakers.

The House and Senate are expected to vote on the deal Thursday.

"Never again will survivors and responders be forced to walk the halls of Congress, begging for their health care. Never again will they lose sleep over fear that this life-saving program will run out," Rep. Carolyn Maloney, D-N.Y., said in a statement Tuesday evening.

After weeks of uncertainty, Ray Pfeifer, a retired New York firefighter with stage four renal cancer linked to his time at Ground Zero, was relieved but asked, "What took ‘em so long?"

"To put first responders through the loop and use us as a political football was just wrong. The heartache everyone had to endure, it was horrible," Pfeifer told NBC News on Tuesday. "I am so happy that thousands of first responders will rest easy and know that they are finally taken care of."

"Now those who rushed to the towers will know that if they get sick because of their bravery, the federal government will be there for them the way they were there for us," said Sen. Chuck Schumer, D-N.Y. "It took too long but Congress finally rose to its responsibility to help our heroes."

Jack McNamara, 9, second from right, holds a sign on behalf of his late father during a rally calling for the funding of the Zadroga Act on Dec. 6, 2015, in New York.Mark Lennihan / AP

Getting taken care of was no easy task.

Despite being told by the Environmental Protection Agency back in 2001 that the air around Ground Zero was safe to breathe, many first responders developed cancers and other debilitating illnesses related to their recovery work. It has been determined that many, including Zadroga himself, died because of their exposure to the Ground Zero toxins.

Nevertheless, Congress has been slow to act on ensuring the responders permanent health care. Even with overwhelming bipartisan support for the legislation, some House and Senate Republicans viewed the program as an unfunded entitlement program and sought to limit its size and duration.

This drew anger from comedian Jon Stewart, who guilt-tripped Congress into originally appropriating the funds back in 2010 and has been a passionate advocate for the first responders ever since.

Stewart visited Capitol Hill twice this fall to bring attention to the expiring funds with dozens of 9/11 first responders by his side, including Pfeifer.

"It’s always happy to see (activist John Feal) and all the other first responders that are ill have to come down here and convince senators who are hiding in their offices and sending out staffers to try and run interference to do the right thing," Stewart told NBC News in an interview in early December.

Stewart also reappeared on late-night television for the first time since his retirement imploring people to push their member of Congress to support the Zadroga Act extension. Due to Stewart, the hashtag #WorstResponders started trending on Twitter and more attention was paid to the plight of the first responders.

While the health care portion of the Zadroga Act is extended through 2090, the other component, the September 11th Victim Compensation Fund is only extended for an additional five years and adds $4.6 billion to pay claims.

The legislation provides that all injured responders and survivors that have already received an award determination will not see cuts to their awards and will get them a year earlier than expected. There are also some changes to the process for those responders who have not yet received an award.

"This is the strongest possible deal we could have negotiated in this Congress," Maloney noted.

Ahead of the bills expected passage, New York Republican Rep. Peter King told NBC News: "Passing the Zadroga bill was a long hard fight for the brave cops, firefighters and construction workers who put their lives and health on the line at Ground Zero. They deserve the very best medical care and treatment and I was proud to be part of this successful effort."

Frank Thorp V

Frank Thorp V is a producer and off-air reporter covering Congress for NBC News, managing coverage of the Senate.

Alex Moe

Alex Moe is a Capitol Hill producer for NBC News covering the House of Representatives.

Luke Russert

Luke Russert joined NBC News in August 2008 as a correspondent based in Washington, D.C. Russert currently reports from Capitol Hill on the House of Representatives for “Nightly News with Brian Williams,” “TODAY,” MSNBC and NBCNews.com.

Since late 2011 Russert has served as a guest host on various MSNBC programs including: “Way Too Early” “The Daily Rundown with Chuck Todd” “Andrea Mitchell Reports” “NOW with Alex Wagner” and “The Cycle.”

From March 2006-2010, Russert co-hosted the sports radio talk show "60/20 Sports" with political pundit James Carville on Sirius-XM Satellite Radio. On "60/20 Sports" he interviewed the likes of former President Clinton, former President George Bush, Bill Russell, Cal Ripken Jr. and Lance Armstrong.

In May of 2009, Russert was honored with the Marlin Fitzwater Award for Leadership in Public Communication from Franklin Pierce University, an award meant to honor individuals who have made significant contributions to public discourse in the spirit of a healthy democracy. He’s also received an honorary degree from Wingate University in North Carolina.

Russert graduated from Boston College with a double major in history and communications. He is the son of the late Tim Russert and Vanity Fair writer Maureen Orth. Russert lives in Washington, D.C., with his pug Chamberlain.